Field of the Invention
The present disclosure relates to the field of display technology, and particularly, to a thin film transistor (TFT), a method of manufacturing the same, an array substrate and a display apparatus.
Description of the Related Art
An organic light-emitting diode (OLED) display may be made to be lighter and thinner, has a larger visual angle and no radiation, and significantly saves electric energy. Thus, the OLED display dominates in the flat panel display apparatus market, and is considered as the most likely new flat panel display of next generation. In an active matrix OLED, a thin film transistor is provided for each pixel as a switch to control each pixel. The thin film transistor typically comprises a gate electrode 20, a source electrode and a drain electrode 60, a gate insulating layer 30 and an active layer 40, as shown in FIGS. 1a-1d. 
Both oxides, such as an indium gallium zinc oxide (IGZO), an indium tin zinc oxide (ITZO) and the like, and amorphous silicon, can be used as materials for manufacturing the active layer of the thin film transistor. Compared to the TFT using the amorphous silicon as material of the active layer (also referred as “amorphous silicon thin film transistor”), the TFT using the oxide as material of the active layer (also referred as “oxide thin film transistor”) has a carrier concentration which is about ten times of that of the amorphous silicon thin film transistor, and a carrier mobility which is 20 to 30 times of that of the amorphous silicon thin film transistor. Thus, the oxide thin film transistor can greatly increase charging and discharging rates to a pixel electrode through the thin film transistor and thus increase a response speed of the pixel, thereby achieving a quicker refresh rate. The oxide thin film transistor is applicable in situations where a quick response and a larger current are required, such as a high frequency, high resolution and large-sized display, an organic light emitting display or the like. Therefore, the oxide thin film transistor becomes a semiconductor component for the new generation LCD and OLED display apparatus.
In a manufacturing process of the oxide thin film transistor, it is required to add an etching barrier layer 50 after the active layer (oxide layer) 40 is manufactured to prevent the active layer from being damaged when the metal of the source and drain electrodes is etched, due to the special characteristics of the oxide. However, during the film forming and photo etching process for the active layer, the pattern of the active layer may be incomplete due to dust or the like, which is shown as a star pattern 40a in FIG. 1a. During the subsequent etching process for the etching barrier layer 50, the gate insulating layer 30 below the pattern of the active layer may be etched together, so that a gate line 20 is exposed, as shown in FIGS. 1b and 1c. The exposed gate line 20 may electrically contact the metal of the source and drain electrodes directly, so that a short circuit (DGS) is formed, as shown in FIG. 1d, thereby affecting the product yield seriously.
FIG. 2 is a schematic plan view of an existing thin film transistor, wherein, the numeral reference 20 indicates a gate electrode, the numeral reference 40 indicates an active layer, the numeral reference 50 indicates an etching barrier layer, the numeral reference 310 indicates a data signal line, the numeral reference 320 indicates via holes in the etching barrier layer, the numeral reference 340 indicates a pixel electrode, and the numeral reference 330 indicates via holes above the pixel electrode. In the prior art, after the position where the short circuit occurs is found, as shown by the black circle R in FIG. 2, it is repaired typically by cutting off a source signal input end of a TFT switch, as shown by the black short line L in FIG. 2. After the source signal input end is cut off, however, the corresponding pixel will become a dark pixel, that is, a defect pixel, due to lacking the source driving. If there are a plurality of short circuit positions on a display panel, a plurality of defect pixels will be generated after repair. As the display panel on which there are a plurality of defect pixels cannot be normally used, it should be disposed as scrap, thereby affecting the useful life of the display panel greatly.